New ‘molecular leaf’ uses solar power to covert CO2 to carbon monoxide

Scientists have developed the most efficient method yet to reduce rising carbon dioxide in the atmosphere, in a process reported earlier this month. The ‘molecular leaf,’ created by an international team of researchers led by Liang-shi Li at Indiana University, uses light or electricity to recycle carbon dioxide, converting it to carbon monoxide. The molecular leave accomplishes this conversion more efficiently than any other existing method.

An associate professor at the IU Bloomington College of Arts and Science’s Department of Chemistry, Li explained:

“If you can create an efficient enough molecule for this reaction, it will produce energy that is free and storable in the form of fuels. This study is a major leap in that direction.”

Burning fuel such as carbon monoxide releases carbon dioxide as well as energy. Converting carbon dioxide back to carbon monoxide needs at least as much energy as is released by burning carbon monoxide. So far, this process has only worked in one direction, leading to a buildup of carbon dioxide in the atmosphere. Scientists have sought to reduce the additional energy needed for the process by increasing efficiency and with the use of solar power.

The molecular leaf achieves this goal, requiring less energy than any process so far to yield carbon monoxide. It uses a nanographene that employs a dark color to absorb as much sunlight as possible. The molecule then uses an atomic rhenium “engine” to yield carbon monoxide.

Scientists have said there is a 95 percent probability that greenhouse gases from human activity have contributed to rising temperatures over the last 50 years. Global levels of carbon dioxide in the atmosphere have risen from 280 parts per million to 400 parts per million in a century and a half.

Li said he is hoping to improve on the molecular leaf design by creating a molecule that lasts longer, and can survive in a non-liquid state, which would be more useful in real world applications. His team is also seeking to replace use manganese in place of rhenium, since it is more common and affordable.